The present invention relates to a drying apparatus and more particularly to an improvement of a drying apparatus having an open-ended drum supported rotatably about a horizontal axis.
In conventional types of drying apparatus, an air inlet port having a filter is provided, for instance, in the front part or panel of the cabinet, while an exhaust port having a filter is provided at the central portion of the rear wall of the open-ended rotatable drum. The filter in the air inlet port catches any dust in the air which is introduced through an air inlet port, and the filter in the exhaust port catches any lint contained in the exhaust air. With such a construction, however, although the inspection and cleaning of the air inlet portion can be carried out easily, inspection and cleaning of the filter in the exhaust port are difficult because in its rearward position of the drum it is hardly accessible.
Recently, a construction has been proposed (but does not form part of the prior art) wherein the air inlet port with its filter and the exhaust port with its filter are both provided in the front part or panel of the cabinet at a position adjacent to the door on both sides thereof for facilitating the inspection and cleaning operation. In this case, the air inlet port communicates with an air path defined between the side wall of the cabinet and a peripheral surface of the drum, while the exhaust port communicates with the interior of the same drum. It is desirable from the viewpoint of operational convenience that the opening for placing materials or clothes into the drum and taking them out is disposed at a central position of the front portion or panel of the cabinet.
Thus, considering an ordinary arrangement having the center of rotation of the drum coincident with the center of the opening, i.e., the door, if the diameter of a front opening portion or open-end of the drum is increased and the area of the exhaust port facing the front opening portion of the drum is also increased for improving the air exhausting efficiency, the area of the air inlet port facing the air path defined between the side wall of the cabinet and the peripheral surface of the drum is reduced, thereby reducing the efficiency of the air induction operation. Conversely, if the diameter of the front opening portion of the drum is reduced and the area of the exhaust port facing the front opening portion of the drum is increased for improving the efficiency of the air induction operation, the area of the exhaust port facing the front opening portion of the drum is reduced, thereby reducing the exhausting efficiency. In either of these cases, a desired amount of ventilation cannot be attained, and the internal temperature of the drum rises up excessively, causing disadvantages such as discoloration of the materials being dried, or thermal deformation of any of the parts of the apparatus which are made of a plastic material.